I am a new owner and new to the site.

The landing gear down light on my 112A is no longer illuminating even though the landing gear is down and locked. I noticed this after I turned on the master before starting. The previous flight had no issues. However, a flight about 2 weeks prior I notice the light out during approach and I just touch the light and it came back to life.

So now my quest to find the issue begins.

I have spoken with Honeywell that make the micro-switches. Actually the tech I spoke with was very helpful. He walked me though testing out the switch and gave me some hints to what to look for.

Here are the symptoms and what I have tried:

1)      With the master on the light does NOT illuminate even when on the ground and the gears are locked.

2)      I have swapped the bulb in the panel socket to one of the other 2 gear down sockets to verify that it’s not the bulb. It worked fine.

3)      I tested the voltage going to the socket and it is exactly the same as the other sockets that seem are working.

4)      I checked the continuity of the switch and checked for a short in the switch. (The Honeywell tech walked me through this). It seemed fine but I did not feel 100% confident that I was doing everything correct.

5)      I checked for high impedance splices in any wire connections I could find.

Now… Here is the interesting thing.

When I push on the switch just enough to make it believe that the landing gear is UP the landing gear light comes on, the warning bell goes on and the pump goes on. It’s almost like the switch is working the opposite way it’s supposed to.

Could I have a short or a bad ground? ANY ideas?

Gary McElwee

N1218J